Point of interest database maintenance system

ABSTRACT

A method of processing data at a server  302  for maintenance of a database  516  of points of interest, such as speed limit enforcement devices. Each of the devices represented in the database has at least one attribute and a confidence value indicative of the accuracy of the at least one attribute associated therewith. The confidence value is time dependent and varies according to a predefined decay function. A report  500  relating to an attribute of a speed limit enforcement device is received at the server  302  from a mobile device  200 . The confidence value associated with the speed limit enforcement device is adjusted in accordance with the received report, and information relating to the speed limit enforcement device  520, 522  is selectively transmitted to the or another mobile device  200  based on the confidence value.

FIELD OF INVENTION

The present invention, at least in some aspects, relates to methods andsystems of processing data for maintenance of a database of points ofinterest, such as speed limit enforcement devices. Other aspects of theinvention relate to the maintenance of similar data that is temporary ordynamical in nature, such as the availability of parking spaces or theavailability and status of electric vehicle charging stations.

BACKGROUND TO THE INVENTION

Portable navigation devices (PNDs) that include GNSS (Global NavigationSatellite Systems) signal reception and processing functionality arewell known and are widely employed as in-car or other vehicle navigationsystems. Such devices include a GNSS antenna, such as a GPS antenna, bymeans of which satellite-broadcast signals, including location data, canbe received and subsequently processed to determine a current locationof the device. The device may also include electronic gyroscopes andaccelerometers which produce signals that can be processed to determinethe current angular and linear acceleration. The determined accelerationmay then be used in conjunction with location information derived fromthe GPS signal to determine the velocity and relative displacement ofthe device and thus vehicle in which it is typically mounted. Suchsensors are most commonly provided in in-vehicle navigation systems, butmay also be provided in the PND itself.

In recent years, GPS has also been used in systems to warn drivers ofspeed traps, enforcement cameras and road hazards, such as school zones,accident black spots, etc. In such systems, a device having a GPSantenna and access to a database containing the location of speed traps,accident black spots, etc is typically provided in a vehicle. The deviceis configured to provide warnings to a driver when the vehicle, usingthe location information derived from the GPS signal, is in the vicinityof one of the locations stored in the database. One such system isdescribed, for example, in WO 01/55744 A2.

As will be appreciated by those skilled in the art, one of the importantaspects of such systems is the accuracy and freshness of the informationin the database. For example, it is undesirable to provide a warning toa user of a speed camera that is no longer present on the stretch ofroad, or to incorrectly indicate the speed limit on a stretch roadassociated with a speed camera in the database. In an effort to improveaccuracy and freshness of such data, it is known to collect and utilisereports from drivers and other users indicating the presence or absenceof speed cameras, and to provide this updated information to othermembers of the community in a real-time manner.

An example of one such system is the Trapster® application for mobiledevices, and which is described in detail at www.trapster.com. In thisapplication, all users of the app are asked to report or validate thestatus of speed traps, enforcement cameras and the like. As result ofthese reports, a digital map can be shown to a user with various iconsand colours representing different trap types, and in some cases theirassociated confidence levels. For example: a green trap icon isdisplayed to indicate the presence of an unverified trap; a yellow trapicon is displayed to indicate that a trap has been verified by anotheruser; a red trap icon is displayed to indicate that a trap has beenverified by multiple users, and thus has the highest confidence levelassociated with it. The application also allows users to reportrelatively short-lived hazards, such as: police traps, e.g. an activesighting of a police speed trap, or a police vehicle currently observingtraffic; construction zones, e.g. road works; brush fires; roadclosures; children at play; icy roads; etc. These hazards are shown toother users, again by means of an icon on the digital map, but willautomatically expire after a certain period of time following the lastpositive report from a user confirming its presence. The particularperiod of time that elapses before a hazard is no longer shown to a uservaries based on the type of hazard. For example, a police trap expiresafter one hour, road closures after six hours and a construction zoneafter five days.

Despite the improvements in speed trap and enforcement camera warningsystems through the use of so-called active community feedback, e.g. asdescribed above in relation to the Trapster® application, the Applicantbelieves that there remains scope for further improvement, and inparticular with respect to the accuracy and freshness of data in theassociated database.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention there is provided amethod of processing data for maintenance of a database of points ofinterest (POI), each point of interest represented in the databasehaving at least one attribute and a confidence value indicative of theaccuracy of the at least one attribute associated therewith, wherein theconfidence value is time dependent and varies according to a predefinedfunction, the method comprising:

receiving a report relating to an attribute of a point of interest;

adjusting the confidence value associated with the point of interest inaccordance with the received report; and

transmitting information relating to the point of interest to a remotedevice based on the confidence value associated with the point ofinterest.

Further, and in accordance with another aspect of the invention there isprovided a system, optionally a server system, arranged to process datafor maintenance of a database of points of interest (POI), each point ofinterest represented in the database having at least one attribute and aconfidence value indicative of the accuracy of the at least oneattribute associated therewith, wherein the confidence value is timedependent and varies according to a predefined function, the systemcomprising:

communication means for receiving a report relating to an attribute of apoint of interest; and

means for adjusting the confidence value associated with the point ofinterest in accordance with the received report;

wherein the communication means is further arranged to transmitinformation relating to the point of interest to a remote device basedon the confidence value associated with the point of interest.

The present invention in this further aspect may include any or all ofthe features described in relation to the first aspect of the invention,and vice versa, to the extent that they are not mutually inconsistent.Thus, if not explicitly stated herein, the system of the presentinvention may comprise means for carrying out any of the steps of themethod described.

The means for carrying out any of the steps of the method may comprise aset of one or more processors configured, e.g. programmed, for doing so.A given step may be carried out using the same or a different set ofprocessors to any other step. Any given step may be carried out using acombination of sets of processors.

The present invention relates to the creation and maintenance of adatabase of points of interest (POI). The term “point of interest” takesit usual meaning within the art and thus refers to a permanent ortemporary object at a particular location, e.g. point or region, that isof interest to a person or company. A POI may therefore be a building,such as a shop, tourist attraction or the like, or an area such as park.Similarly, a POI may be an object such as a speed limit enforcementdevice, e.g. a fixed speed camera (either individual cameras or as partof average speed zones), mobile speed camera, etc, or an dynamicadvertising space (capable of displaying data sent to it from a remotelocation).

Each POI represented in the database has one or more associatedattributes, preferably a plurality of such attributes. For example, in apreferred embodiment of the invention where the POI database is adatabase of speed limit enforcement devices, these attributes caninclude the type of speed camera, the location of the camera, the speedlimit associated with the camera, and the driving direction associatedwith the camera. Each POI also has at least one associated confidencevalue which is indicative of the accuracy of one, some or all of theassociated attributes.

The database, which is typically stored on a server or is accessible bya server, is maintained by receiving reports from various sources, suchas mobile devices, data obtained from web crawlers, etc, containinginformation indicating whether the current attributes for a POI arecorrect or not. The system of the present invention therefore comprisescommunication means for transmitting data to, and receiving data from, aplurality of remote devices. These reports are used to adjust, e.g.increase or decrease, a confidence value associated with a POI in thedatabase. The confidence value, as described below, ages according to apredefined function, such that the confidence value changes over time(even without reports being received for the POI).

Data relating to a POI is transmitted to one or more remote devices(e.g. devices, such as mobile devices, that are spatially remote fromthe database) in dependence on the confidence value for the POI. Forexample, when the confidence value for a particular POI falls below apredetermined threshold, then updated data relating to the POI may nolonger be transmitted to remote devices. The transmitted data, as willbe discussed in more detail below, is preferably indicative of least oneof the confidence value or an attribute of the POI, and can be used, forexample when the POI is a speed limit enforcement device, by the remotedevice to determine whether to provide alerts or warnings to a driver ornot.

The use of confidence values that age according to a predefinedfunction, and which can preferably also be adjusted positively ornegatively following received reports, e.g. from mobile devices,moderators or third party data, enables a greater degree of control whenfusing data from numerous sources to allow for an increased level offreshness and accuracy. For example, in the known arrangements describedabove, map data in the database is always present for a certain periodof time following the last report from a user supporting the presence ofthe device. In contrast, in the present invention, a POI such as a speedlimit enforcement device can rapidly be made inactive, i.e. such that noalerts or warnings are provided to a user, thereby reducing the numberof false positives often experienced with such systems.

The method of the present invention relates to the maintenance of adatabase of points of interest. The invention will be described in thefollowing passages in relation to a database of speed limit enforcementdevices. It will be appreciated, however, that the methods of theinvention are equally applicable to any type of point of interest, andare not limited only to speed limit enforcement devices. Accordingly, inthe following, the term “speed limit enforcement device” can be replacedby the term “point of interest”, unless the context requires otherwise.

The speed limit enforcement devices in the database can comprise anytype of device that can be used to enforce the speed limit assigned to aroad, such as a fixed devices, e.g. speed cameras, red lights cameras,and mobile devices, such as those contained in parked vehicles or heldby law enforcement officers.

The method may be implemented by a processing resource of a server, e.g.with the database of speed limit enforcement devices being stored at thesever. Alternatively, or additionally if there are multiple databases,e.g. of differing levels of quality, richness (amount of detail), etc,one or more of the databases may be stored remotely from the server, butbe accessible by the processing resource of the server via suitablecommunications link. The link may be a wireless link or a wired link ormay comprise combinations thereof.

Each speed limit enforcement device in the database maintained accordingto the present invention has at least one attribute associated with it,together with a confidence value indicative of the accuracy of the leastone attribute. In some embodiments, there may only be a single attributeassociated with a speed limit enforcement device, although preferably atleast some, and typically all, of the devices have a plurality ofassociated attributes.

The at least one attribute associated with a speed limit enforcementdevice can be one or more of: a device type; a location of the device; aspeed limit; a driving direction indicating with which direction ofvehicular travel the device operates (or in other words with which sideof the road the device is positioned to monitor); a time period duringwhich the device is operational; and an indication of the number ofreports submitted by users in respect of the device.

The device type attribute may indicate that the device is any suitableand desired form of speed limit enforcement device. For example, thedevice type attribute may indicate that the device is a fixed speedcamera, or that the device is a mobile speed camera. The device typeattribute may also indicate whether the camera is used in conjunctionwith one or more other cameras as part of an average speed trap (i.e.where a vehicle's speed is monitored over a relatively long distance,such as a number of kilometres, to ensure that the average speed of thevehicle does not exceed the legal speed limit). As will be discussed inmore detail below, the type of the speed limit enforcement device may beused to determine the confidence value decay profile to be used with adevice.

The device location attribute indicates the geographic location of thespeed limit enforcement device. The attribute may represent a pointlocation, e.g. as a longitude and latitude pair, or with reference to aroad segment in an electronic map. For example, the location couldindicate that the speed limit enforcement device is a certain distancealong a road segment of an electronic map, and may also indicate onwhich side of the road segment the device is located. The locationreference could be made with respect to a particular electronic map, orthe location reference could be map-agonistic by being generated using adynamic location referencing method, such as AGORA-C or OpenLR®. Thedevice location attribute may alternatively represent an area, insteadof a point, such as a geographic area or a portion of a road segment.Such an area may be used, for example, where the speed limit enforcementdevice is part of an average speed trap; the area may thereforerepresent the road between the start and end of the average speed zone.An area could also be used when, for example, legislation within aterritory does not permit a driver to know the exact location of a speedlimit enforcement device, but only a zone having a device locatedtherein.

The speed limit attribute indicates a speed limit associated with anenforcement device which may be used by a mobile device to providesuitable warnings to a user. The attribute may be the actual speed limitfor the road on which the enforcement device is located, e.g. havingbeen received from third party or Government data, or after having beenconfirmed from user reports or mobile mapping data. Alternatively, thespeed limit attribute may be derived from position data received fromvehicles travelling along the road segment on which the device islocated. For example, the position data can be processed to determine anaverage speed for the road segment, and the speed limit attribute forthe device is set, at least initially, as the determined average speed.

A speed limit enforcement device may have a plurality of speed limitattributes, e.g. if the speed limit for a road varies throughout theday, such as having a different value during hours of peak traffic; orif the speed limit for a road varies throughout the week, such as havinga different value on the weekend. Similarly, a speed limit enforcementdevice may also have an associated temporal attribute that indicatestimes at which the device is operational. This may be beneficial inareas where construction work is taking place, and speed cameras areonly active during periods when working is taking place.

The driving direction attribute may indicate that the speed limitenforcement device is only applicable when a driver is travelling in onedirection along a road. Alternatively, the attribute may indicate thatthe device is applicable to vehicles travelling in both directions alonga road. The absence of a driving direction attribute may similarlyindicate that the device operates in both directions of travel.

The attribute providing an indication as to the number of reportssubmitted in respect of a device can take any form as desired. Forexample, the attribute may indicate one or more of: the total number ofreports submitted for a device; the number of reports submitted insupport of a device; and the number of reports submitted requestingdeletion of a device. The attribute may be indicative of the number ofreports received over the entire lifetime of a device in the database,or over a particular time period. For example, it is therefore envisagedthat each received report may be binned into one of a plurality oftemporal periods, such as weekly, daily, hourly, etc.

As will be appreciated, the database of speed limit enforcement devicesin the present invention is continually being updated with new devices,or with changes to devices already existing in the database, based atleast on reports from users. Speed limit enforcement devices canadditionally be entered and/or modified in the database in a number ofother possible ways.

For example, third party data could be used to supply the initiallocations and attributes of speed limit enforcement devices. Moderatorscould also manually add speed limit enforcement devices to, or modifydevices in, the database, e.g. after validating a user report indicatingthe presence of a device, or after identifying the presence of a devicefrom aerial, satellite or mobile mapping vehicle images.

In addition, or alternatively, the presence of speed cameras could beinferred from changes in the vehicle speed.

For example, and as described in WO 2011/023719 A1, the entire contentsof which is incorporated herein by reference, mobile devices carried byvehicles can detect a particular speed profile, such as a reduction inspeed, followed by a substantially constant speed at or below the speedlimit for the road, potentially followed by an increase in speed. Areport may then be sent from the mobile device to a server indicatingthe location of the vehicle at the time the characteristic speed changeis detected. The report could also include information relating to otherattributes of a potential speed limit enforcement device, e.g. thedirection of travel of the vehicle, the speed of the vehicle during thesubstantially constant speed phase of the profile, etc. Such reports maybe used to add speed limit enforcement devices to, or modify devices in,the database of the present invention.

It is also envisaged that position data relating to the position of avehicle at different times when travelling along a route, and which isreceived at a server, can be used to infer the presence of a speed limitenforcement device. Typically, such position data is obtained from aplurality of different vehicles. The position data received frommultiple mobile devices travelling along the same navigable segment canbe processed to infer the position of a speed limit enforcement device,e.g. by identifying changes in vehicle speed characteristic of a speedlimit enforcement device. The determined speed limit enforcement devicemay then be added to the database, together with an associatedconfidence value. The associated confidence value may be such thatwarnings or alerts concerning a speed limit enforcement device inferredin this manner are not provided to drivers until at least one driver hasconfirmed the presence of the device. Further details concerning thecalculation of confidence values, and how the confidence value effectsthe way in which a speed limit enforcement device is handled by thesystem, are provided below. One or more attributes associated with aspeed limit enforcement device, in addition to a location, can also beinferred from the position data, e.g. a speed limit, driving direction,etc.

In the present invention, a confidence value is associated with eachspeed limit enforcement device in the database. The confidence value isrepresentative of how certain it is that the device is actually presentin reality and/or how certain it is that the attributes associated withthe device are correct.

As will be appreciated, a device may have a single associated confidencevalue, or alternatively it may have a plurality of confidence values,e.g. one for each of the attributes associated with a device. If adevice has a single associated confidence value, then this value may beindicative of the accuracy of a single attribute, but in a preferredembodiment it may represent a combined confidence value indicative ofthe accuracy of a plurality, and preferably each, of the attributesassociated with the device.

The confidence value may take any suitable form, but preferably at anypoint in time it is a value between a minimum and maximum value, e.g.between 0 and 1, or between 0% and 100%. The minimum value indicatingthat there is no confidence in the attribute associated with theconfidence value. Conversely, the maximum value indicating that there isno doubt as to the accuracy of the attribute associated with theconfidence value.

In aspects of the present invention, the confidence value is not onlytime-dependent, i.e. varying in time due to the receipt of reports frommobile devices (and users thereof) either supporting, requesting changesto, or deletion of, a device in the database, but it also is arranged tovary according to a predefined function. In other words, when a speedlimit enforcement device is added in the database, i.e. time t=0, it isassigned an initial confidence value C(t=0)=C₀. This initial confidencevalue then changes over time in dependence on a function f(t), such thatat a later point in time T, assuming no reports, either positive ornegative, have been received for a device, then the device will have aneffective confidence value:

C _(effective)(t=T)=ƒ(T)C ₀

Typically, however, reports will be received in respect of a device, andthus the confidence value for a device at a point in time T′ will alsobe based, at least, on any received reports. Accordingly, the effectiveconfidence value for a device will typically be:

C _(effective)(t=T′)=ƒ(T′)C(T′)

The predefined function can be of any suitable and desired form. Forexample, the predefined function can be a growth function, i.e. causingthe confidence value to increase over time. In preferred embodiments ofthe invention, however, and for example in embodiments relating to speedlimit enforcement devices, the predefined function is a decay function,i.e. causing the confidence value to decrease (or age) over time.

As will be appreciated, the term “confidence value” used herein will,unless the context requires otherwise, refer to the actual confidencevalue associated with a speed limit enforcement device in the databaseat a particular point in time. Accordingly, in embodiments where theconfidence value changes according to a predefined function, e.g. decayor growth profile, the term “confidence value” will refer to theeffective confidence value, i.e. wherein the confidence value determinedas a result of user reports (and an initial confidence value) is furthermodified according to the decay or growth profile.

The initial confidence value for a device in the database can bedetermined in any suitable and desired manner. In preferred embodiment,however, the initial confidence value will be based on the manner inwhich the speed limit enforcement device is added to the database, or inother words the source of the speed limit enforcement device.

For example, in some embodiments, the initial confidence value may befixed value, e.g. when the device is added based on third party data orby a moderator. In such circumstances, the initial confidence value willtypically be relatively high, e.g. at or close to the maximum value, asthe information obtained from these sources is typically of a highquality. A different fixed value may be used for each source, e.g. afirst initial confidence value may be used when the data is obtainedfrom a first company, whilst a second initial confidence value may beused when the data is obtained from a second different company.

In other embodiments, for example when the presence of a speed limitenforcement device is inferred from detected changes in vehicular speed,e.g. from the processing of received position data, the initialconfidence value may be based on the received position data. Typically,the initial confidence value associated with devices added to thedatabase from such sources will be relatively low.

In yet other embodiments, for example where the presence of a speedlimit enforcement device is determined following the receipt of a reportfrom a mobile device, the initial confidence value may be based on atrust level of the user who submitted the report. For example, arelatively high initial confidence value may be associated with a speedlimit enforcement device if the user has a history of submitting highquality, accurate reports. Conversely, a relatively low confidence valuemay be associated with a device if the user has a history of submittingpoor quality, inaccurate reports.

The predefined function, e.g. decay function, that is used to age theconfidence value associated with a speed limit enforcement device in thedatabase can also be of any suitable and desired form. For example, thedecay function may be at least one of: a linear function, an exponentialfunction, and a polynomial (e.g. quadratic, cubic, etc) function.

As will be appreciated, the confidence value of the present invention ispreferably arranged to vary between a maximum and minimum value and maybe at one or more intermediate values therebetween. Accordingly, a step(or Heaviside) function should not be considered to be a growth or decayfunction within the scope of the present invention.

The same function, e.g. decay function, may be used for all speed limitenforcement devices in the database, such that confidence in all devicesdecays at the same rate. Alternatively, in other embodiments, differentfunctions may be used with different speed limit enforcement devices inthe database. For example, a function may be selected for use with adevice based on at least one attribute associated with the device,preferably the device type attribute. For example, a first decayfunction may be used with fixed speed limit enforcement devices, and asecond decay function used with mobile speed limit enforcement devices.In such embodiments, the first decay function preferably decays slowerthan the second decay function, such that fixed devices should remainactive in the system longer than mobile devices.

As will be appreciated, the server system of the present inventioncommunicates with one or more remote devices to ensure that the data inthe speed limit enforcement device database is accurate and up to date.The remote devices, i.e. devices that are spatially remote from theserver system, can be of any suitable form. For example, the informationfrom the server system may be sent to fixed location devices, e.g. homecomputers and the like. In a preferred embodiment, however, the remotedevices are mobile devices that are preferably of a form where they canbe carried or transported in a vehicle. The mobile devices may beportable devices, e.g. capable of being handheld, and which, forexample, may be removably mounted within a vehicle. Alternatively, oradditionally, the mobile devices may be in-vehicle systems, i.e. devicesthat are permanently mounted within vehicles.

As will be appreciated, the mobile devices are preferably capable ofdetermining the current position of the device, and thus preferablycomprise location determining means. The location determining meanscould be of any type. For example, a mobile device could comprise meansfor accessing and receiving information from WiFi access points orcellular communication networks, and using this information to determineits location. In preferred embodiments, however, a mobile devicecomprises a global navigation satellite systems (GNSS) receiver, such asa GPS receiver, for receiving satellite signals indicating the positionof the receiver at a particular point in time, and which preferablyreceives updated position information at regular intervals.

The mobile devices may also include means for determining the relativedisplacement of the vehicle in which the device is carried, therebyallowing, for example, the speed and driving direction of the vehicle atany point in time to be determined. The means could comprise one or moreelectronic gyroscopes or accelerometers in the device, or the devicecould have access to such sensors in the vehicle itself, e.g. using thevehicle CAN bus.

Accordingly, in preferred embodiments, the mobile devices that areutilised in the present invention comprise navigation apparatus, such asportable navigation devices (PNDs) that can be removably mounted withina vehicle or in-vehicle navigation systems, and which preferably includeGNSS signal reception and processing functionality. It will beappreciated, however, that the mobile devices may also comprise mobiletelephones, PDAs, tablet computers or the like running suitable softwareprograms.

The mobile devices also comprise communication means for transmittingand receiving information from the system, e.g. server, of the presentinvention. The information, as will be discussed in more detail below,may comprise reports indicating new speed limit enforcement devices orerrors associated with speed limit enforcement devices already in thedatabase. The information may comprise data indicative the confidencevalue, or effective confidence value, associated with a speed limitenforcement, and/or data indicative of an attribute associated with aspeed limit enforcement device. The communication means could be of anytype. For example, the devices may comprise one or more physicalconnector interfaces by means of which power and/or data signals can betransmitted to and received from the device. In preferred embodiments,however, the communication means comprises one or more wirelesstransmitters/receivers to allow communication over cellulartelecommunications and other signal and data networks, for example WiFI,Wi-Max, GSM and the like.

As will be appreciated, the mobile devices also comprise means foralerting a user to the presence of a speed limit enforcement device, andoptionally providing additional information relating to the device, suchas the speed limit. The alert could be one or more of a visual alert, anaudio alert and a haptic alert.

In embodiments of the present invention, reports are received frommobile devices containing information indicating the presence of a newspeed limit enforcement device and/or whether the current attributes fora speed limit enforcement device are correct or not. These reports willtypically be generated in response to a user input, e.g. by the userinputting information on a mobile device indicating a new speed limitenforcement device or an error in an already exiting device. It is alsoenvisaged, however, that reports could be automatically generated,partially or fully, by the mobile device.

For example, in a preferred embodiment, a user may input on the mobiledevice the presence of a speed limit enforcement device, such as bypressing a hard button or soft (or virtual) key on the device. The usermay additionally input one or more attributes associated with the speedlimit enforcement device. Alternatively, or additionally, these otherattributes may be automatically generated by the device, such as bysetting the current vehicle location, speed and/or driving direction asthe location, speed limit and driving direction attributes,respectively, for the device.

In other embodiments, and if, for example, the mobile device receivesimages of a vehicle's surroundings from a camera feed, image recognitiontechniques could be used to automatically determine the presence ofspeed limit enforcement devices on the images received from the camerafeed.

Each received report preferably includes at least one modified or newattribute value associated with a speed limit enforcement device. Eachreport may include only a single attribute value for a device, or it mayinclude a plurality of attribute values. As discussed above, one or moreof the attribute values may be input by a user or be automaticallygenerated by the mobile device.

Reports may be determined to relate to the same speed limit enforcementdevice using any suitable method. For example, if the location of thespeed limit enforcement device in the report is within a predetermineddistance of the location of a speed limit enforcement device alreadyexisting in the database, then the reports can be said to relate to thesame device.

The received reports are preferably used to modify the attributesassociated with a speed limit enforcement device and/or adjust, e.g.increase or decrease, as necessary, the confidence value of the speedlimit enforcement device referred to the report.

The attributes associated with a speed limit enforcement device may bemodified in any suitable and desired manner. For example, the locationof the device may be modified so as to be the average of the currentlocation and the location indicated in the report. Similarly, the speedlimit of the device may be modified so as to be the average of thecurrent speed limit and the speed limit indicated in the report. Theaverage may be a weighted average, e.g. based on a trust level of thesource of the report, such as the user that submitted the report.

The confidence value for a speed limit enforcement device at aparticular point in time, before the impact of aging according to thepredetermined function is taken into account, is, at least in part,dependent on reports received from mobile devices (and thus users)relating to the particular speed limit enforcement device. Theconfidence value can be calculated in any suitable manner, butpreferably it will utilise one of more of the following: the number ofpositive reports received (where a positive report is one that supportsthe continued existence of a speed limit enforcement device in thesystem); the number of negative reports received (where a negativereport is one that supports the removal of a speed limit enforcementdevice in the system); the ratio of positive reports received tonegative reports; the age of a report (e.g. newer reports are viewed asbeing more relevant than older reports); and the confidence valueassociated with each individual attribute, e.g. a location confidence, aspeed limit confidence and/or a type confidence.

The confidence value associated with a speed limit enforcement device inthe database can be used in a number of advantageous ways in embodimentsof the present invention. In particular, in the present invention,information relating to a speed limit enforcement device is transmittedto one or more remote devices based on the confidence value for thespeed limit enforcement device in the database.

The information relating to a speed limit enforcement device may be ofany suitable and desired form. For example, the information may beindicative of an attribute of a speed limit enforcement device, and mayinclude: an attribute or attributes of a new device recently added tothe database; or a recently changed attribute relating to speed limitenforcement device already existing in the database. Updated informationrelating to speed limit enforcement device can therefore be provided tousers.

The information may, alternatively or additionally, be indicative of theconfidence value of a speed limit enforcement device. For example, in apreferred embodiment, the confidence value associated with a speed limitenforcement device can be used as an indication that the device shouldbe active in the database, i.e. the device continues to exist inreality, or inactive, i.e. the device no longer exists in reality, andthus whether a mobile device should provide warnings or alerts to adriver in relation to the speed limit enforcement device in question. Inother words, when the confidence value of a speed limit enforcementdevice in the database falls below a predetermined threshold, then it isassumed that the device is no longer present in the real world, anddrivers are no longer informed about the device. This thereforesignificantly reduces the number of false positive warnings that arecommonly provided to drivers in known systems.

Thus, in embodiments of the invention, the method comprises transmittingan indication to one or more mobile devices that alerts relating to thepresence of a speed limit enforcement device should no longer be issuedto a user. The indication may be transmitted when the confidence valueassociated with the speed limit enforcement device is below apredetermined threshold. Alternatively, the indication may betransmitted each time there is a change in the confidence value of aspeed limit enforcement device due to a received report.

The indication sent to the one or more mobile devices can be of anysuitable and desired form. For example, in embodiments where theindication is transmitted when the confidence value falls below athreshold value, the indication could be a list of one or more devicesthat have changed from being active to inactive, or vice versa.Alternatively, if the indication is sent whenever there is a change inconfidence value due to a received report, the server system maytransmit an updated confidence value for an enforcement device, and thedetermination as to whether a speed limit enforcement device is activeor inactive is made on the mobile device itself. In other embodiments,rather than sending an updated confidence value, the server system maytransmit a time when alerts for a speed limit enforcement device are nolonger to be issued; the time being based on when the current confidencevalue for the speed limit enforcement is due to fall below the thresholdlevel according to the predetermined decay function.

As will be appreciated, when a device is made inactive in the database,it may actually be deleted from the database. Alternatively, the devicemay remain in the database, e.g. for future reference or to be madeactive again at a later date. For example, a mobile speed camera may beintermittently used for at the same location, and thus may be active orinactive at different times.

The information transmitted to one or more mobile devices may,alternatively or additionally, be a request to provide confirmation ofan attribute of a speed limit enforcement device, or data that causessuch a request to be generated on the mobile device. The attribute mayinclude the presence of the speed limit enforcement, or it may relate toinformation about the device itself, such as the associated speed limitor driving direction. By actively requesting feedback from users toconfirm information about, and in particular the presence of, a speedlimit enforcement device, the confidence in a device can be quicklyincreased to a high level or decreased to a low level (such that thedevice can be made inactive in the database).

Thus, in embodiments of the invention, the method comprises transmittinga request to one or more mobile devices to provide confirmation of anattribute of a speed limit enforcement device when the confidence valueassociated with the speed limit enforcement device is below apredetermined threshold. A report is preferably received from one ormore of the remote, e.g. mobile, devices in response to the request, andthe confidence value associated with the speed limit enforcement deviceadjusted accordingly.

In other embodiments, the method comprises transmitting data to one ormore mobile devices each time there is a change in the confidence valueof a speed limit enforcement device due to a received report, the datacausing a request to be generated on the mobile device to provideconfirmation of an attribute of a speed limit enforcement device. Thedata may be a time when the request is to be provided to a user; thetime being based on when the current confidence value for the speedlimit enforcement is due to fall below the threshold level according tothe predetermined decay function.

It is believed that the use of confidence values associated with pointsof interest, such as speed limit enforcement devices, to requestfeedback from users may be new and advantageous in its own right.

Thus, in accordance with a further aspect of the invention there isprovided a method of processing data for maintenance of a database ofpoints of interest (POI), each point of interest represented in thedatabase having at least one attribute and a time-varying confidencevalue indicative of the accuracy of the at least one attributeassociated therewith, the method comprising:

transmitting a request to one or more remote devices to provideconfirmation of an attribute of a point of interest when the confidencevalue associated with the point of interest is below a predeterminedthreshold;

receiving a report relating to the attribute in response to thetransmitted request; and

adjusting the confidence value associated with the point of interest inaccordance with the received report.

In accordance with another aspect of the invention there is provided asystem, optionally a server system, arranged to process data formaintenance of a database of points of interest (POI), each point ofinterest represented in the database having at least one attribute and atime-varying confidence value indicative of the accuracy of the at leastone attribute associated therewith, the system comprising:

communication means for transmitting a request to one or more remotedevices to provide confirmation of an attribute of a point of interestwhen the confidence value associated with the point of interest is belowa predetermined threshold; and

means for adjusting the confidence value associated with the point ofinterest in accordance with a report received by the communication meansin response to the transmitted request.

The present invention in any of these further aspects may include any orall of the preferred and optional features described herein asappropriate. For example, the points of interest in the database may bespeed limit enforcement devices, and the attribute of the speed limitenforcement device can be any one or more of: the presence of thedevice; the device type; the location of the device; the speed limitassociated with the device; the driving direction indicating with whichdirection of vehicular travel the device operates; and the time periodduring which the device is operational. In embodiments, the confidencevalue may also vary according to a predefined growth or decay function,such as a linear, exponential or polynomial function.

The means for carrying out any of the steps of the method may comprise aset of one or more processors configured, e.g. programmed, for doing so.A given step may be carried out using the same or a different set ofprocessors to any other step. Any given step may be carried out using acombination of sets of processors.

In preferred embodiments of the invention, the system uses at least twopredetermined thresholds with regard to the confidence value.

For example, in one embodiment, when the confidence value for a speedlimit enforcement device falls below a first predetermined threshold,then a request is sent to one or more remote, e.g. mobile, devices toprovide confirmation of an attribute of the speed limit enforcementdevice. Further, when the confidence value for a speed limit enforcementdevice falls below a second predetermined threshold, the secondthreshold being less than the first threshold, then an indication istransmitted to one or more remote, e.g. mobile, devices that alertsrelating to the presence of a speed limit enforcement device should nolonger be issued to a user.

In another embodiment, each time the confidence value for a speed limitenforcement device changes due to a received report, a plurality of timevalues can be sent to one or more remote, e.g. mobile, devices. Theplurality of time values comprise a first time value indicating the timeat which the confidence value of the speed limit enforcement device willfall below a first predetermined threshold (based on the predetermineddecay function). At the time indicated by the first time value, arequest will be generated and provided to a user on the mobile deviceasking for confirmation of an attribute of the speed limit enforcementdevice. The plurality of time values also comprise a second time valueindicating the time at which the confidence value of the speed limitenforcement device will fall below a second predetermined threshold(based on the predetermined decay function), the second threshold beingless than the first threshold. At the time indicated by the second timevalue, alerts relating to the presence of the speed limit enforcementdevice will no longer be issued to the user on the mobile device. Theplurality of time values may also comprise a third time value indicatingthe time at which the confidence value of the speed limit enforcementdevice will fall to zero or another suitable value (based on thepredetermined decay function). At the time indicated by the third timevalue, the speed limit enforcement device will be

The above embodiments are described with reference to confidence valuesthat age according to a predetermined decay function; thus actions aresaid to be taken when the confidence value falls below certain thresholdlevels. As will be appreciated, however, in embodiments where theconfidence value varies according to a predetermined growth function,actions will in contrast be taken when the confidence value rises abovecertain threshold levels.

As will be appreciated from the above, information relating to speedlimit enforcement devices is regularly transmitted to one or moreremote, e.g. mobile, devices. This information may be transmitted to allmobile devices, whether the information will be of use to them in thenear future or not. Preferably, however, the information relating to aspeed limit enforcement device is transmitted only to devices that are,or will be, in the vicinity of the device. This therefore reduces theamount of information that needs to be transmitted to mobile devices.

Thus, for example, one or more mobile devices may provide the system,e.g. server, with location information relating to at least one of acurrent or future location. For example, a mobile device may provide aplanned route of travel to the server. This location information canthen be used by the system to select the mobile devices that shouldreceive, preferably over the air (OTA) using wireless communicationmeans, database changes and requests to confirm an attribute of speedlimit enforcement devices. Accordingly, in embodiments, informationrelating to new and changed speed limit enforcement devices may betransmitted only to mobile devices that are or will be passing thelocations associated with speed limit enforcement devices. Similarly,attribute confirmation requests may be transmitted only to mobiledevices that have recently passed or will pass the particular speedlimit enforcement device in question.

As will be appreciated, the present invention extends to a mobiledevice, optionally a navigation device, configured to operate with thesystem as described above.

Similarly, the present invention also extends to a database of points ofinterest (POI), such as speed limit enforcement devices, generatedand/or maintained using the above described method of the presentinvention.

It will also be appreciated by those skilled in the art that all of thedescribed aspects and embodiments of the present invention can, andpreferably do, include, as appropriate, any one or more or all of thepreferred and optional features described herein.

The methods in accordance with the present invention may be implementedat least partially using software. It will thus be seen that, whenviewed from further aspects, the present invention extends to a computerprogram product comprising computer readable instructions adapted tocarry out any or all of the methods described herein when executed onsuitable data processing means, such as a server system.

The invention also extends to a computer software carrier comprisingsuch software. Such a software carrier could be a physical (ornon-transitory) storage medium or could be a signal such as anelectronic signal over wires, an optical signal or a radio signal suchas to a satellite or the like.

Although the present invention has been described in relation tomaintaining a database of points of interest, and in particular speedlimit enforcement devices, it will be appreciated that similar methodscould be used with any information and/or map data that may, forexample, be temporary in nature and/or requiring regular updates fromusers; in other words dynamic data. For example, it is envisaged thatthe methods of the present invention could be used to maintain adatabase of: parking spaces and/or parking areas, and the availabilitythereof; areas of construction or road works; electric vehicle chargingstations, and the availability thereof; etc.

Thus, for example, in embodiments relating to parking spaces and/orparking areas, which comprise a plurality of parking spaces, the atleast one attribute associated with each parking space and/or area cancomprise one or more of: a location of the space and/or area; anavailability of the space and/or area; and times when the space and/orarea are available for use.

Similarly, in embodiments relating to electric vehicle chargingstations, the at least one attribute associated with each chargingstation can comprise one or more of: a location of the charging station;an availability of the charging station; a type of the charging station(e.g. quick charge, slow charge, etc); and times when the chargingstation can be used.

It is also envisaged that the methods of the present invention can beused in dynamic signage, i.e. electronic displays that show information,such as television programs, menus, advertising, etc. In suchembodiments, certain information could be displayed for longer periodsof time based on a number of positive votes received from the generalpublic.

The present invention in any of these further aspects may include any orall of the preferred and optional features described herein asappropriate.

The means for carrying out any of the steps of the method may comprise aset of one or more processors configured, e.g. programmed, for doing so.A given step may be carried out using the same or a different set ofprocessors to any other step. Any given step may be carried out using acombination of sets of processors.

Advantages of these embodiments are set out hereafter, and furtherdetails and features of each of these embodiments are defined in theaccompanying dependent claims and elsewhere in the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the teachings of the present invention, andarrangements embodying those teachings, will hereafter be described byway of illustrative example with reference to the accompanying drawings,in which:

FIG. 1 is a schematic illustration of a Global Positioning System (GPS);

FIG. 2 is a schematic illustration of electronic components arranged toprovide a navigation device;

FIG. 3 is a schematic illustration of the manner in which a navigationdevice may receive information over a wireless communication channel;

FIG. 4 is a perspective view of a navigation device;

FIG. 5 shows how the confidence value for fixed and mobile speed camerasages over time when no user reports are received; and

FIG. 6 shows how the confidence value for a speed camera varies overtime when user reports are received;

FIG. 7 is a schematic representation of an exemplary server system inaccordance with the present invention.

Like reference numerals are used for the like features throughout thedrawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a method and system for processingdata to maintain a database of speed limit enforcement devices. In orderto keep the data in the database accurate and up to date, the systemutilises information in the form of reports received from a plurality ofmobile devices. In other words, the system relies on a community ofusers to continually supply information on new speed limit enforcementdevices not already in the database, and to validate the detailsassociated with the devices already in the database.

The mobile devices can be of any suitable form, but in illustrativeembodiments are navigation apparatus, such as portable navigationdevices (PNDs). Preferred embodiments of the present invention will nowbe described with particular reference to a PND. It should beremembered, however, that the teachings of the present invention are notlimited to PNDs but are instead universally applicable to any type ofprocessing device that is configured to warn or alert drivers when theyare approaching speed limit enforcement devices using a local and/orremote database listing such devices. It follows therefore that in thecontext of the present invention, the mobile devices could be a PND, anavigation device built into a vehicle, or indeed a computing resource(such as a desktop, portable personal computer (PC), tablet computer,mobile telephone or portable digital assistant (PDA)).

FIG. 1 illustrates an example view of Global Positioning System (GPS),usable by navigation devices. Such systems are known and are used for avariety of purposes. In general, GPS is a satellite-radio basednavigation system capable of determining continuous position, velocity,time, and in some instances direction information for an unlimitednumber of users. Formerly known as NAVSTAR, the GPS incorporates aplurality of satellites which orbit the earth in extremely preciseorbits. Based on these precise orbits, GPS satellites can relay theirlocation to any number of receiving units.

The GPS system is implemented when a device, specially equipped toreceive GPS data, begins scanning radio frequencies for GPS satellitesignals. Upon receiving a radio signal from a GPS satellite, the devicedetermines the precise location of that satellite via one of a pluralityof different conventional methods. The device will continue scanning, inmost instances, for signals until it has acquired at least threedifferent satellite signals (noting that position is not normally, butcan be determined, with only two signals using other triangulationtechniques). Implementing geometric triangulation, the receiver utilizesthe three known positions to determine its own two-dimensional positionrelative to the satellites. This can be done in a known manner.Additionally, acquiring a fourth satellite signal will allow thereceiving device to calculate its three dimensional position by the samegeometrical calculation in a known manner. The position and velocitydata can be updated in real time on a continuous basis by an unlimitednumber of users.

As shown in FIG. 1, the GPS system is denoted generally by referencenumeral 100. A plurality of satellites 102 are in orbit about the earth104. The orbit of each satellite 102 is not necessarily synchronous withthe orbits of other satellites 102 and, in fact, is likely asynchronous.A GPS receiver 106 is shown receiving spread spectrum GPS satellitesignals 108 from the various satellites 102.

The spread spectrum signals 108, continuously transmitted from eachsatellite 102, utilize a highly accurate frequency standard accomplishedwith an extremely accurate atomic clock. Each satellite 102, as part ofits data signal transmission 108, transmits a data stream indicative ofthat particular satellite 102. It is appreciated by those skilled in therelevant art that the GPS receiver device 106 generally acquires spreadspectrum GPS satellite signals 108 from at least three satellites 102for the GPS receiver device 106 to calculate its two-dimensionalposition by triangulation. Acquisition of an additional signal,resulting in signals 108 from a total of four satellites 102, permitsthe GPS receiver device 106 to calculate its three-dimensional positionin a known manner.

FIG. 2 is an illustrative representation of electronic components of anavigation device 200 according to a preferred embodiment of the presentinvention, in block component format. It should be noted that the blockdiagram of the navigation device 200 is not inclusive of all componentsof the navigation device, but is only representative of many examplecomponents.

The navigation device 200 is located within a housing (not shown). Thehousing includes a processor 202 connected to an input device 204 and adisplay screen 206. The input device 204 can include a keyboard device,voice input device, touch panel and/or any other known input deviceutilised to input information; and the display screen 206 can includeany type of display screen such as an LCD display, for example. In aparticularly preferred arrangement the input device 204 and displayscreen 206 are integrated into an integrated input and display device,including a touchpad or touchscreen input so that a user need only toucha portion of the display screen 206 to select one of a plurality ofdisplay choices or to activate one of a plurality of virtual buttons.

The navigation device 200 may include an output device 208, for examplean audible output device (e.g. a loudspeaker). As output device 208 canproduce audible information for a user of the navigation device 200, itis should equally be understood that input device 204 can include amicrophone and software for receiving input voice commands as well.

In the navigation device 200, processor 202 is operatively connected toand set to receive input information from input device 204 via aconnection 210, and operatively connected to at least one of displayscreen 206 and output device 208, via output connections 212, to outputinformation thereto. Further, the processor 202 is operably coupled to amemory resource 214 via connection 216 and is further adapted toreceive/send information from/to input/output (I/O) ports 218 viaconnection 220, wherein the I/O port 218 is connectible to an I/O device222 external to the navigation device 200. The memory resource 214comprises, for example, a volatile memory, such as a Random AccessMemory (RAM) and a non-volatile memory, for example a digital memory,such as a flash memory. The external I/O device 222 may include, but isnot limited to an external listening device such as an earpiece forexample. The connection to I/O device 222 can further be a wired orwireless connection to any other external device such as a car stereounit for hands-free operation and/or for voice activated operation forexample, for connection to an ear piece or head phones, and/or forconnection to a mobile phone for example, wherein the mobile phoneconnection may be used to establish a data connection between thenavigation device 200 and the internet or any other network for example,and/or to establish a connection to a server via the internet or someother network for example.

FIG. 2 further illustrates an operative connection between the processor202 and an antenna/receiver 224 via connection 226, wherein theantenna/receiver 224 can be a GPS antenna/receiver for example. It willbe understood that the antenna and receiver designated by referencenumeral 224 are combined schematically for illustration, but that theantenna and receiver may be separately located components, and that theantenna may be a GPS patch antenna or helical antenna for example.

Further, it will be understood by one of ordinary skill in the art thatthe electronic components shown in FIG. 2 are powered by power sources(not shown) in a conventional manner. As will be understood by one ofordinary skill in the art, different configurations of the componentsshown in FIG. 2 are considered to be within the scope of the presentapplication. For example, the components shown in FIG. 2 may be incommunication with one another via wired and/or wireless connections andthe like. Thus, the scope of the navigation device 200 of the presentapplication includes a portable or handheld navigation device 200.

In addition, the portable or handheld navigation device 200 of FIG. 2can be connected or “docked” in a known manner to a vehicle such as abicycle, a motorbike, a car or a boat for example. Such a navigationdevice 200 is then removable from the docked location for portable orhandheld navigation use. As an example, FIG. 4 shows a navigation device200 that may sit on an arm 252, which itself may be secured to a vehicledashboard, window, etc using a suction cup 254. This arm 252 is oneexample of a docking station to which the navigation device 200 can bedocked. The navigation device 200 can be docked or otherwise connectedto the arm 252 of the docking station by snap connecting the navigationdevice to the arm, for example. To release the connection between thenavigation device 200 and the docking station, a button on thenavigation device 200 may be pressed, for example. Other equallysuitable arrangements for coupling and decoupling the navigation deviceto a docking station are well known to persons of ordinary skill in theart.

Referring now to FIG. 3, the navigation device 200 may establish a“mobile” or telecommunications network connection with a server 302 viaa mobile device (not shown) (such as a mobile phone, PDA, and/or anydevice with mobile phone technology) establishing a digital connection(such as a digital connection via known Bluetooth technology forexample). Thereafter, through its network service provider, the mobiledevice can establish a network connection (through the internet forexample) with a server 302. As such, a “mobile” network connection isestablished between the navigation device 200 (which can be, and oftentimes is mobile as it travels alone and/or in a vehicle) and the server302 to provide a “real-time” or at least very “up to date” gateway forinformation.

The establishing of the network connection between the mobile device(via a service provider) and another device such as the server 302,using an internet (such as the World Wide Web) for example, can be donein a known manner. This can include use of TCP/IP layered protocol forexample. The mobile device can utilize any number of communicationstandards such as CDMA, GSM, WAN, etc.

As such, an internet connection may be utilised which is achieved viadata connection, via a mobile phone or mobile phone technology withinthe navigation device 200 for example. For this connection, an internetconnection between the server 302 and the navigation device 200 isestablished. This can be done, for example, through a mobile phone orother mobile device and a GPRS (General Packet Radio Service)-connection(GPRS connection is a high-speed data connection for mobile devicesprovided by telecom operators; GPRS is a method to connect to theinternet).

The navigation device 200 can further complete a data connection withthe mobile device, and eventually with the internet and server 302, viaexisting Bluetooth technology for example, in a known manner, whereinthe data protocol can utilize any number of standards, such as the GSRM,the Data Protocol Standard for the GSM standard, for example.

The navigation device 200 may include its own mobile phone technologywithin the navigation device 200 itself (including an antenna forexample, or optionally using the internal antenna of the navigationdevice 200). The mobile phone technology within the navigation device200 can include internal components as specified above, and/or caninclude an insertable card (e.g. Subscriber Identity Module or SIMcard), complete with necessary mobile phone technology and/or an antennafor example. As such, mobile phone technology within the navigationdevice 200 can similarly establish a network connection between thenavigation device 200 and the server 302, via the internet for example,in a manner similar to that of any mobile device.

For GPRS phone settings, a Bluetooth enabled navigation device may beused to correctly work with the ever changing spectrum of mobile phonemodels, manufacturers, etc; model/manufacturer specific settings may bestored on the navigation device 200, for example. The data stored forthis information can be updated.

In FIG. 3 the navigation device 200 is depicted as being incommunication with the server 302 via a generic communications channel318 that can be implemented by any of a number of differentarrangements.

The server 302 and a navigation device 200 can communicate when aconnection via communications channel 318 is established between theserver 302 and the navigation device 200 (noting that such a connectioncan be a data connection via mobile device, a direct connection viapersonal computer via the internet, etc).

The server 302 includes, in addition to other components which may notbe illustrated, a processor 304 operatively connected to a memory 306and further operatively connected, via a wired or wireless connection314, to a mass data storage device 312. The processor 304 is furtheroperatively connected to transmitter 308 and receiver 310, to transmitand send information to and from navigation device 200 viacommunications channel 318. The signals sent and received may includedata, communication, and/or other propagated signals. The transmitter308 and receiver 310 may be selected or designed according to thecommunications requirement and communication technology used in thecommunication design for the navigation system 200. Further, it shouldbe noted that the functions of transmitter 308 and receiver 310 may becombined into a signal transceiver.

Server 302 is further connected to (or includes) a mass storage device312, noting that the mass storage device 312 may be coupled to theserver 302 via communication link 314. The mass storage device 312contains a store of navigation data and map information, and can againbe a separate device from the server 302 or can be incorporated into theserver 302.

The navigation device 200 is adapted to communicate with the server 302through communications channel 318, and includes processor, memory, etcas previously described with regard to FIG. 2, as well as transmitter320 and receiver 322 to send and receive signals and/or data through thecommunications channel 318, noting that these devices can further beused to communicate with devices other than server 302. Further, thetransmitter 320 and receiver 322 are selected or designed according tocommunication requirements and communication technology used in thecommunication design for the navigation device 200 and the functions ofthe transmitter 320 and receiver 322 may be combined into a singletransceiver.

Software stored in server memory 306 provides instructions for theprocessor 304 and allows the server 302 to provide services to thenavigation device 200. One service provided by the server 302 involvesprocessing requests from the navigation device 200 and transmittingnavigation data from the mass data storage 312 to the navigation device200. Another service provided by the server 302 includes processing thenavigation data using various algorithms for a desired application andsending the results of these calculations to the navigation device 200.

The communication channel 318 generically represents the propagatingmedium or path that connects the navigation device 200 and the server302. Both the server 302 and navigation device 200 include a transmitterfor transmitting data through the communication channel and a receiverfor receiving data that has been transmitted through the communicationchannel.

The communication channel 318 is not limited to a particularcommunication technology. Additionally, the communication channel 318 isnot limited to a single communication technology; that is, the channel318 may include several communication links that use a variety oftechnology. For example, the communication channel 318 can be adapted toprovide a path for electrical, optical, and/or electromagneticcommunications, etc. As such, the communication channel 318 includes,but is not limited to, one or a combination of the following: electriccircuits, electrical conductors such as wires and coaxial cables, fibreoptic cables, converters, radio-frequency (RF) waves, the atmosphere,empty space, etc. Furthermore, the communication channel 318 can includeintermediate devices such as routers, repeaters, buffers, transmitters,and receivers, for example.

In one illustrative arrangement, the communication channel 318 includestelephone and computer networks. Furthermore, the communication channel318 may be capable of accommodating wireless communication such as radiofrequency, microwave frequency, infrared communication, etc.Additionally, the communication channel 318 can accommodate satellitecommunication.

The communication signals transmitted through the communication channel318 include, but are not limited to, signals as may be required ordesired for given communication technology. For example, the signals maybe adapted to be used in cellular communication technology such as TimeDivision Multiple Access (TDMA), Frequency Division Multiple Access(FDMA), Code Division Multiple Access (CDMA), Global System for MobileCommunications (GSM), etc. Both digital and analogue signals can betransmitted through the communication channel 318. These signals may bemodulated, encrypted and/or compressed signals as may be desirable forthe communication technology.

The server 302 includes a remote server accessible by the navigationdevice 200 via a wireless channel. The server 302 may include a networkserver located on a local area network (LAN), wide area network (WAN),virtual private network (VPN), etc. In other embodiments, the server 302may include a personal computer such as a desktop or laptop computer,and the communication channel 318 may be a cable connected between thepersonal computer and the navigation device 200. Alternatively, apersonal computer may be connected between the navigation device 200 andthe server 302 to establish an internet connection between the server302 and the navigation device 200. Alternatively, a mobile telephone orother handheld device may establish a wireless connection to theinternet, for connecting the navigation device 200 to the server 302 viathe internet.

The navigation device 200 may be provided with information from theserver 302 via information downloads which may be periodically updatedautomatically or upon a user connecting navigation device 200 to theserver 302 and/or may be more dynamic upon a more constant or frequentconnection being made between the server 302 and navigation device 200via a wireless mobile connection device and TCP/IP connection forexample. For many dynamic calculations, the processor 304 in the server302 may be used to handle the bulk of the processing needs, however,processor 210 of navigation device 200 can also handle much processingand calculation, oftentimes independent of a connection to a server 302.

As is known in the art, the navigation device 200 may be configured toprovide warnings when a vehicle is approaching a speed limit enforcementdevice, such as a mobile or fixed speed camera. In particular, thewarning may be provided when the vehicle is approaching the speed limitenforcement device at a speed that is above the legal speed limit forthe road. The warnings may comprise a visual warning on the display 206of the navigation device 200, an audible warning, a haptic warning, orany combination thereof as desired. In order to provide such warnings,the navigation device has access to a database of speed limitenforcement devices, which includes at least the location of speed limitenforcement device and a speed limit for the device. The database willtypically be stored on the navigation device 200, e.g. in the memory214, and will be regularly updated with new data from the server 302using the communication channel 318. It is envisaged, however, that thenavigation device 200 may only temporary store portions of the databasefor speed limit devices in their immediate vicinity or a planned route.

The speed cameras in the database each have at least one attribute, andtypically a plurality of attributes, associated therewith. Theattributes can be, for example: a location of the speed camera; a speedlimit associated with the camera; the side of the road on which thespeed camera is operational; and the type of the speed camera (e.g. afixed camera, a mobile camera, part of an average speed trap).

Due to the nature of speed cameras, e.g. new fixed speed cameras arecontinually being installed, fixed speed cameras may be moved to a newlocation, mobile speed cameras will often be in operation for shortperiods of time, etc, the information in the database on the server 302needs to be constantly refreshed to ensure that it is accurate and up todate. To facilitate this process, speed cameras in the database eachhave an associated confidence value, which reflects how certain it isthat the speed camera is actually still there in the real world and howcertain it is that the attributes for the speed camera in the databaseare actually correct. The confidence value for a particular speed cameracan take a value between 0% and 100%, where 0% means that there iscompletely no confidence in the camera and conversely 100% means thatthere is complete confidence in the camera.

As will be appreciated, the confidence value for a camera will changewith time as reports are received from users either in support of, orrequesting deletion of, the camera. A report in support of a camera willcause the confidence value to increase, while a report requestingdeletion of a camera will cause the confidence value to decrease. Itwill be understood that a report supporting a camera may be a reportsimply confirming the presence of the camera or it may be a reportrequesting the modification of an attribute associated with the camera.

In addition to the confidence value varying in time due to receivedreports, the confidence value associated with a speed camera is alsodesigned to vary in time, or age, according to a predetermined decayfunction. This aging of the confidence value is depicted in FIG. 5.

It has been recognised that it is desirable to have different decayfunctions based on the type of the speed camera. For example, and asshown in FIG. 5, a fixed speed camera (shown as a dashed line) ages at aslower rate than a mobile speed camera (shown as a solid line). This isto reflect the reality that a mobile speed camera will in all likelihoodhave a significantly shorter lifetime than a fixed speed camera. Anydecay function can be used as desired, but it can include a linear, anexponential or a polynomial (e.g. quadratic, cubic, etc) decay function.

As will be appreciated, the decay functions shown in FIG. 5 show how theconfidence value associated with a fixed and mobile speed camera changewhen no reports for the cameras are received from users. In practice,reports are continually being received in relation to a speed camera,thereby pushing the confidence value for the camera up or down. This isshown in FIG. 6, wherein: 410 shows the confidence value decreasingaccording to the predefined decay function; 412 shows the confidencevalue increasing due to a received report; and 414 shows the confidencevalue decreasing due to a received report.

The manner by which the confidence value for a particular speed camerais determined will be described in more detail below following adescription of the architecture of the system in accordance with anembodiment of the present invention with reference to FIG. 7.

As shown in FIG. 7, new speed cameras can be identified, andsubsequently added to the speed camera database 516, in a number ofways.

For example, the existence of a speed camera may be determined followingthe receipt of a report from a user 500. The user reports may begenerated in any manner on the navigation devices 200 as appropriate.For example, the navigation device may have a hard button or soft key(on a touch screen display) that can be pressed to automaticallygenerate and transmit a report to the server 302. Such a report mayinclude the location, speed and/or direction of travel of the navigationdevice (and thus the vehicle) at the time the button is pressed.Additional or more accurate information about a speed camera maysubsequently be added to a report by the user before it is transmittedto the server 302. For example, the user may provide the actual speedlimit for the road and may also adjust the location of the speed cameraas appropriate (e.g. as the location of the device provided in thereport will not always reflect the actual position of the speed camera,but will typically be a short distance before or after the actualposition of the camera).

Speed camera data can also be obtained from various third parties 502,such as government data, other companies newspapers and otherjournalistic sources, etc. The existence of speed cameras canadditionally be determined from sources, such as images collected bymobile mapping vehicles, and confirmed by moderators 504. It is alsoenvisaged that location of speed cameras can be inferred from changes inthe speed of individual vehicles or collections of vehicles 506.

New speed cameras, or modifications to attributes of existing speedcameras, obtained from one or more of the sources 500, 502, 504 and 506are received at a fusion engine 510 of the server 302. It will beunderstood by those skilled in the art, however, that speed camerainformation may be obtained from other sources, in addition to thosedescribed above. At the fusion engine 510, the received speed camerainformation may be combined with one or more of: (i) information alreadyexisting in a speed camera database 516; (ii) information from a mapdatabase 512, e.g. to identify the location of a speed camera; and (iii)information from a user trust database 514, e.g. to provide anindication as to accuracy of reports previously received from aparticular user. The information from all these sources is combined bythe fusion engine 510 to produce new or amended speed cameras entries inthe speed camera database 516.

For example, when a first report is received indicating the presence ofa new speed camera, a new entry is made in the database. The attributesfor the speed camera will be taken, at least in part, from theinformation contained in the report. Accordingly, the speed camera willbe assigned a type: fixed or mobile, if available, or the type will bedetermined from the determined type confidence level as described below.The location, speed and driving direction for the camera will be thatcontained in the report if available, otherwise they will be left blankor inferred from other sources, such as the map database, data frommobile mapping vehicles, video from camera-equipped navigation devices,etc.

When a subsequent report relating to the same speed camera is received,the location of the speed camera will be adjusted according to aweighted average of the locations contained in the reports, theweighting being based on the trust level of the source of the reports,e.g. that of the user submitting the report. The speed limit of thespeed camera will similarly be adjusted according to weighted average ofthe speeds contained in the reports based on trust level.

The fusion engine 510 also serves to generate a confidence value for newspeed cameras that are added to the database 516, and modify theconfidence value as necessary (e.g. following user reports) for speedcameras already existing in the database 516. A new confidence value isdetermined each time a new report is received, unless the report isreceived from a completely distrusted source.

The confidence value C for a speed camera is calculated by the fusionengine 510 as a compound value according to the following formula:

$\begin{matrix}{C = {\gamma {\sum\limits_{i = 1}^{N}{c_{i}\lambda_{i}}}}} & {{Eqn}.\mspace{14mu} 1}\end{matrix}$

c is the partial confidences of attributes associated with the speedcamera (e.g. location, speed, type and size),λ is a weight for each partial confidence, i.e. the contribution made byeach confidence type to the total confidence, andγ is the weighted ratio between supporting and deletion reports.

The weights λ are normalised such that:

$\begin{matrix}{{\sum\limits_{i = 1}^{N}\lambda_{i}} = 1} & {{Eqn}.\mspace{14mu} 2}\end{matrix}$

In a preferred example, the weight associated with the size confidenceis 80%, the weight associated with the type confidence is 5%, the weightassociated with the speed confidence is 5% and the weight associatedwith the location confidence is 10%. It will be appreciated, however,that the weight for each partial confidence can take any value asdesired provided the requirement of Equation 2 is fulfilled.

The weighted ratio γ is a number between 0 and 1 that represents thefraction of supporting reports received for a speed camera, i.e. thosereports that support the hypothesis that a speed camera is present, inrelation to all reports for that speed camera. The reports in the ratioare weighted such that a newer report carries more weight than an olderreport.

The partial confidences that are used to determine the confidence valueC are: location confidence c_(L); speed confidence c_(S); fixed typeconfidence c_(Tf); mobile type confidence c_(Tm); and size confidencec_(N).

The location confidence c_(L) provides an indication as to the accuracyof the estimated location of the speed camera, and is determined basedon a weighted average of the distance between the location contained ina report and the current speed camera location, the weighting beingbased on user trust level. The location confidence is calculated in amanner such that it is zero when the weighted average exceeds a maximumvalue.

The speed confidence c_(S) provides an indication as to the accuracy ofthe estimated speed limit associated with the speed camera. The speedconfidence c_(S) is calculated using a statistical measure of thedifferent speeds received in relevant reports, each report beingweighted according to the trust level of the source, e.g. of the user. Areport is deemed relevant if it contains speed limit information in agiven speed range, e.g. 0 to 200 km/h, and is not older than apredetermined time period, e.g. 365 days.

The type confidence provides an indication as to the degree ofconfidence there is in the type attribute associated with a speedcamera, e.g. whether it is a fixed speed camera or a mobile speedcamera. As mobile and fixed speed cameras differ significantly in termsof their life and the number of associated reports, confidence iscalculated differently for each type. The type attribute for a speedcamera is set according to the last report from a moderator, or if thereis no such report the type attribute is set using the relative sizes ofc_(Tm) and c_(Tf); with a speed camera being said to be fixed ifc_(Tm)<c_(Tf), and conversely being said to be mobile if c_(Tm)>c_(Tf).

The confidence that a speed camera is a mobile camera c_(Tm) is set as100% if the report came from a moderator, but is otherwise determinedbased on the relative number of reports indicating that a camera is amobile speed camera to the total number of received reports and the ageof the speed camera in the database 510. The c_(Tm) value is calculatedsuch that it is zero when the speed camera has been in the database 510for more than a predetermined period of time, and such that each newreport that is received for a speed camera decreases the confidence thatthe speed camera is a mobile speed camera. This reflects the situationthat mobile speed cameras only exist for a short period of time, andthus if a speed camera exists for a relatively long period of time, thenit becomes more likely that the camera is a fixed speed camera.

The confidence that a speed is a fixed camera c_(Tf) is again set as100% if the report came from a moderator, but is otherwise determinedbased on the age of the camera and also the number of reports receivedrelating to the camera.

The size confidence c_(N) is an indicator of the number of reportsreceived in relation to a particular speed camera. The size confidencec_(N) is calculated such that the first reports received for aparticular speed camera contribute more to the confidence thansubsequent reports.

As discussed above, the confidence value C decays over time according toa predetermined decay function. Thus, when a new report is received fora speed camera already existing in the database 510, the report changesthe aged confidence value, rather than the previously calculatedconfidence value. This is achieved by the introduction of an effectiveconfidence C′, wherein:

C′(t)=ƒ(t)C

The decay function ƒ(t) is, in a preferred embodiment, a linear decayfunction, wherein ƒ(t)=1−mt. The gradient m is based on the type of thecamera, such a fixed speed camera decays slower then a mobile speedcamera. This aging of the confidence value is shown in FIG. 5, whereinthe effective confidence value for a fixed speed camera (dashed line)and a mobile speed camera (solid line) is depicted, for speed cameras onwhich no reports are received.

The varying confidence values, or to be more accurate the effectiveconfidence values, for each of the speed cameras in the database 510 arecontinually monitored by the confidence value monitoring engine 518 (asshown in FIG. 6). The purpose of the monitoring engine 518 is todetermine when the confidence value for any speed camera falls below oneof two predefined thresholds. These thresholds 400 and 402 can be seenin FIG. 5.

The first threshold 400 indicates when a speed camera in the database510 is active or inactive. When a speed camera has a confidence valuethat means it is seen as active in the database, then mobile devices 200provide warnings to users as to the presence of the speed camera andupdates relating to the speed camera, e.g. changed attributes, are sentto the mobile devices 200. Conversely, when a speed camera has aconfidence value that means it is seen as inactive, then mobile devices200 do not provide any warnings to users since it is assumed that thespeed camera no longer exists on the road. As will be appreciated, theuse of the first threshold 400 limits the number of false positivesbeing issued by devices.

When a speed camera falls below the threshold 400, then a message 520 issent to users indicating that the speed camera is now inactive. Themessage 520 may include an identifier to identify the speed camera andan indicator that shows the speed camera is inactive. Messages 520 maybe sent to all users as soon as the speed camera falls below thethreshold level 400. Alternatively, messages 520 may just be sent tousers in the vicinity of the speed camera, and other users are informedabout the change in a periodic update of the database 516. This reducesthe number of active/inactive status messages that are sent out tousers, and thus the amount of bandwidth needed for operation of thesystem.

The second threshold 402 indicates the beginning of an intermediatelevel of confidence, which extends between the thresholds 400 and 402.It is desirable for any speed cameras that fall into this region toquickly confirm the presence or absence of a speed camera, and thereforeincrease the confidence value for the camera above the threshold 402 ordecrease the confidence value below the threshold 400. Accordingly, whenthe confidence value for a speed camera falls below the threshold 402,messages 522 are sent to users requesting confirmation of the presenceof a speed camera in the database 510. The messages 522 can also requestthat a user confirm a particular attribute associated with the speedcamera. For example, if the confidence value for a speed camera isreduced due to a lack of confidence in only one attribute, then themessages may ask a user to confirm this attribute. As will beappreciated, the mobile devices 200 periodically provide their currentposition to the server 302, and may also provide a planned route to theserver 302. This information is used by the server 302 to only send themessages 522 to mobile devices 200 that will pass the associated speedcamera.

As will be seen from FIG. 6, the reports received from users in responseto the attribute confirmation requests 522 are supplied to the fusionengine 510 to update the relevant speed cameras in the database 516.

The use of active feedback from users can also be used to confirm thepresence of speed cameras that are inferred indirectly, e.g. fromanalysing vehicle speed data as discussed above (506). For example, oncea speed camera is determined from analysing vehicle speed data it can beassigned a confidence value that will always fall between the thresholds400 and 402. Thus, the presence of the speed camera will quickly beconfirmed or rejected based on the responses of users to the messages522 that are sent out by the server 302.

In other embodiments, instead of sending messages 520 and 522 to themobile devices 200, each time the confidence value of a speed camerachanges due to a received user report 500 or the like (and not only dueto natural decay), then a message is sent to the mobile devicesincluding a first time indicating when the confidence value with fallbelow the second threshold 402 based on the decay function associatedwith the camera, and a second time indicating when the confidence valuewill fall below the first threshold 400 based on the decay functionassociated with the camera. The message may also include a third timevalue indicating when the confidence value falls to a level where thecamera is to be deleted from the database on the mobile devices 200.

The mobile devices will then perform the actions associated with thesetime values. In other words, at the first time, the mobile devices 200will generate a message to show (or provide in some other way) to theuser asking for confirmation as to the existence of the speed camera.Similarly, at the second time, the mobile devices 200 will stopproviding warnings to the driver relating to the speed camera.

It will be appreciated that whilst various aspects and embodiments ofthe present invention have heretofore been described, the scope of thepresent invention is not limited to the particular arrangements set outherein and instead extends to encompass all arrangements, andmodifications and alterations thereto.

For example, whilst the embodiments in the foregoing detail descriptionrefer to specifically to a system for maintaining a database of speedcameras, it will be understood that a similar system could be used withother types of points of interest or dynamic data. In particular, datain an electronic map that is temporary in nature, such as theavailability of parking areas, either individual spaces or multiplespaces in a parking lot, and the availability of electric vehiclecharging stations could be maintained using a similar system to thatdescribed above. The system could also be used to control dynamicadvertising displays.

In this regard, whilst the embodiments in the above detailed descriptionrefer to the use of a predetermined decay function to age the confidencevalues, it will be appreciated that any type of function could be usedin the system. For example, a growth function could be used thatincreases the confidence value with time, or a more complex functionthat both increases and decreases the confidence value with time.

Similarly, whilst embodiments described in the foregoing detaileddescription refer to GPS, it should be noted that the mobile devices200, e.g. navigation apparatus, may utilise any kind of position sensingtechnology as an alternative to, or indeed in addition to, GPS. Forexample, the navigation apparatus may utilise other global navigationsatellite systems, such as the European Galileo system. Equally, it isnot limited to satellite-based systems, but could readily function usingground-based beacons or other kind of system that enables the device todetermine its geographic location.

It will also be well understood by persons of ordinary skill in the artthat whilst the preferred embodiment may implement certain functionalityby means of software, that functionality could equally be implementedsolely in hardware (for example by means of one or more SICs(application specific integrated circuit)) or indeed by a mix ofhardware and software.

Lastly, it should be noted that whilst the accompanying claims set outparticular combinations of features described herein, the scope of thepresent invention is not limited to the particular combinationshereafter claims, but instead extends to encompass any combination offeatures or embodiments herein disclosed irrespective of whether or notthat particular combination has been specifically enumerated in theaccompanying claims at this time.

1. A method of processing data for maintenance of a database of pointsof interest (POI), each point of interest represented in the databasehaving at least one attribute and a time-varying confidence valueindicative of the accuracy of the at least one attribute associatedtherewith, the method comprising: receiving a report relating to anattribute of a point of interest; adjusting the confidence valueassociated with the point of interest in accordance with the receivedreport; and transmitting information relating to the point of interestto a remote device based on the confidence value associated with thepoint of interest.
 2. The method of claim 1, wherein the points ofinterest are speed limit enforcement devices.
 3. The method of claim 2,wherein the at least one attribute associated with a speed limitenforcement device comprises one or more of: an active status of thedevice; a device type; a location of the device; a speed limit; adriving direction indicating with which direction of vehicular travelthe device operates; and a time period during which the device isoperational.
 4. The method of claim 2, wherein the at least oneattribute associated with a speed limit enforcement device comprises adevice type, and the type of the speed limit enforcement device is usedto determine the predefined function associated with the device.
 5. Themethod of claim 2, wherein the at least one attribute associated with aspeed limit enforcement device comprises a speed limit, wherein thespeed limit is one of: (i) the actual speed limit for the road on whichthe speed limit enforcement device is located; and (ii) derived fromposition data received from vehicles travelling along the road on whichthe speed limit enforcement device is located.
 6. The method of claim 2,wherein speed limit enforcement devices are added to and/or modified inthe database based on identifying a change in speed indicative of thepresence of a speed limit enforcement device from position data relatingto the position of at least one vehicle at a plurality of times whentravelling along a route.
 7. The method of claim 2, wherein theinformation relating to a speed limit enforcement device transmitted toa remote device comprises an indication that alerts indicating thepresence of the speed limit enforcement device should no longer beissued to a user by the remote device.
 8. The method of claim 7, whereinthe indication that alerts indicating the presence of the speed limitenforcement device should no longer be issued to a user is transmittedto the remote device when the confidence value for the speed limitenforcement device falls below a first predetermined threshold.
 9. Themethod of claim 1, wherein the points of interest comprise one or moreof: parking locations; electric vehicle charging stations; fuelstations; dynamic advertising locations; and areas of construction orroad works.
 10. The method of claim 1, wherein the confidence value istime dependent and varies according to a predefined function, thepredefined function comprising at least one of: a linear function; anexponential function; and a polynomial function.
 11. The method of claim1, wherein the confidence value is time dependent and varies accordingto a predefined function, the predefined function comprising a decayfunction, a growth function, or a combination thereof.
 12. The method ofclaim 1, wherein the initial confidence value associated with a point ofinterest is based on the source of the point of interest.
 13. The methodof claim 1, wherein each point of interest represented in the databasehas a plurality of attributes associated therewith, and the confidencevalue associated with a device is a combined confidence value indicativeof the accuracy of each of the attributes.
 14. The method of claim 1,wherein the confidence value for a point of interest is calculated usingone or more of: the number of positive reports received from the remotedevices; the number of negative reports received from the remotedevices; the ratio of positive reports received to negative reports; andthe age of each report.
 15. The method of claim 1, wherein theinformation relating to a point of interest transmitted to a remotedevice comprises at least one of: a request to provide confirmation ofthe presence; a request to provide confirmation of an attribute of thepoint of interest; and data that causes such a request to be generatedon the remote device.
 16. The method of claim 15, wherein the request toprovide confirmation of the presence and/or an attribute of the point ofinterest is transmitted to the remote device when the confidence valuefor the point of interest falls below a second predetermined threshold.17. A server system arranged to process data for maintenance of adatabase of points of interest (POI), each point of interest representedin the database having at least one attribute and a time-varyingconfidence value indicative of the accuracy of the at least oneattribute associated therewith, the system comprising memory for storingthe database of points of interest and at least one processor configuredto: receive a report relating to an attribute of a point of interest;and adjust the confidence value associated with the point of interest inaccordance with the received report; and transmit information relatingto the point of interest to a remote device based on the confidencevalue associated with the point of interest.
 18. A non-transitorycomputer readable medium comprising computer program code adapted, whensaid computer program code is run on a computer, to cause the computerto perform a method of processing data for maintenance of a database ofpoints of interest (POI), each point of interest represented in thedatabase having at least one attribute and a time-varying confidencevalue indicative of the accuracy of the at least one attributeassociated therewith, the method comprising: receiving a report relatingto an attribute of a point of interest; adjusting the confidence valueassociated with the point of interest in accordance with the receivedreport; and transmitting information relating to the point of interestto a remote device based on the confidence value associated with thepoint of interest.
 19. (canceled)
 20. The method of claim 1, wherein theinformation relating to the point of interest transmitted to the remotedevice comprises a time when alerts in relation to the point of interestare no longer to be issued to a user on the remote device.